SparkFun Forums

[pgf]

if i got a manual with the quadstepper board, i've lost it. :neutral: and i didn't spot any documents on the product page.

can someone remind me how the current trimpot should be adjusted?

paul

[skimask]

Wha?
The Schematic, Eagle files, Datasheet, Library and GitHub links aren't good enough?
How about that Google...

[pgf]

yes, i suppose that was vague. i meant a "user manual" document.

from the schematic and data sheet, i see that the trimpot adjusts the voltage on the REF input, which is the reference voltage applied to an internal DAC, and it's available at a testpoint, so can see the voltage easily. and i read the paragraph that mentions the REF input, but i confess, it wasn't terribly meaningful to me. i suppose i could try google, but frankly i'm not sure what i'd search for.

none of those things tells me what i probably knew, but have forgotten, which is how i should choose a value for Vref.

[pgf]

i just discovered the rather subtle "comments" tab on the product page.

three years ago, someone asked:

Question: The driver chip datasheet indicates that you can limit current with the reference voltage. Does anyone know how to adjust the motor current limit on the QuadStepper Driver Board?

to which the answer was:

There is a trim pot on the board that will adjust the current limit to the motors. You should trim the board so that each motor isn’t drawing more than an amp or so (in a stall condition).

so i guess the answer is to put an ammeter inline with one of the motor coils, and measure there? do i need to measure both coils at once? if i set the board to no microstepping, then i suppose only one coil will be energized at a time -- is that correct?